Well screen

ABSTRACT

A screen assembly connected about a perforated base pipe includes a filter layer constructed of layers of woven metal cloth sintered together; a drainage layer positioned between the base pipe and the filter layer, the drainage layer sintered to the filter layer; and a support layer constructed of woven metal rods and metal cable disposed about the filter layer, the support layer sintered to the filter layer.

FIELD OF THE INVENTION

The present invention relates to screens used in subsurface wellcompletions, and particularly to screens using mesh media.

BACKGROUND

Screens are commonly used in well completions in which the producingformation is poorly or loosely consolidated. Abrasive particulatesgenerally referred to as “sand” or “fines”, can cause problems ifproduced. For example, the formation surrounding the wellbore can erodeand wash out, potentially leading to collapse of the well. Sand candamage equipment such as pumps or seals as the sand travels at highspeed through the pump or past the seals. Produced sand must be disposedoft, and this imposes an additional cost to the well operator. Fines canclog flow passages, disrupting production.

Often, to enhance filtration, a layer of particles of presorted size,commonly referred to as “gravel”, is injected between the formation (orcasing) and the screen. In those cases, the screen is sized to preventpassage of the gravel. The gravel in turn prevents the passage of fines.

Various screen types are used to prevent the production of sand. Forexample, a perforated base pipe can have wire wrapped around it suchthat the spacing between the wire wraps limits the size of sand that canpass. Mesh material can also be used. However, well screens can beexpensive. Therefore, there is a continuing need for improved designsand manufacturing methods for screens.

SUMMARY OF THE INVENTION

In view of the foregoing and other considerations, the present inventionrelates to wellbore completions and more particularly to sand controlwell screens.

Accordingly, premium mesh-type well screens are provided. In oneexample, a well screen includes a base pipe having perforations and ascreen assembly connected about a portion of the base pipe, wherein anouter shroud is not disposed over the screen assembly.

Another example of a well screen used in a wellbore includes a base pipehaving perforations and a screen assembly having at least three layersinterconnected by diffusion bonding, the screen assembly positionedabout a portion of the base pipe and connected thereto.

In another example, a screen assembly connected about a perforated basepipe includes a filter layer constructed of layers of woven metal clothsintered together; a drainage layer positioned between the base pipe andthe filter layer, the drainage layer sintered to the filter layer; and asupport layer constructed of woven metal rods and metal cable disposedabout the filter layer, the support layer sintered to the filter layer

The foregoing has outlined the features and technical advantages of thepresent invention in order that the detailed description of theinvention that follows may be better understood. Additional features andadvantages of the invention will be described hereinafter which form thesubject of the claims of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and aspects of the present inventionwill be best understood with reference to the following detaileddescription of a specific embodiment of the invention, when read inconjunction with the accompanying drawings, wherein:

FIG. 1 is an exploded view of a well screen of the present invention;and

FIG. 2 is a partially cut-away view of a well screen of the presentinvention.

DETAILED DESCRIPTION

Refer now to the drawings wherein depicted elements are not necessarilyshown to scale and wherein like or similar elements are designated bythe same reference numeral through the several views.

As used herein, the terms “up” and “down”; “upper” and “lower”; andother like terms indicating relative positions to a given point orelement are utilized to more clearly describe some elements of theembodiments of the invention. Commonly, these terms relate to areference point as the surface from which drilling operations areinitiated as being the top point and the total depth of the well beingthe lowest point.

FIG. 1 is an exploded view of a well screen of the present invention,generally denoted by the numeral 10. Well screen 10 includes a base pipe12 and a screen assembly 14. Screen assembly 14 is positioned over aportion of base pipe 12 to facilitate filtered fluid flow into wellscreen 10 and into base pipe 12. Base pipe 12 may be a perforated,slotted, or include one or more inflow control devices (“ICD”) tofacilitate the radial flow of fluid into base pipe 12. It is noted thatan ICD may limit flow, or prevent flow into base pipe 12 in selectedcircumstances. In an example, base pipe 12 may be a non-perforated pipehaving a ICD connected along base pipe 12, for example at the top, andthen base pipe 12 is covered by screen assembly 14.

As is known in the industry, mesh-type well screens include an outershroud surrounding the various mesh layers atop the base pipe. The outershroud serves multiple purposes including protecting the mesh layer whenrunning into the wellbore and during transportation and provides burstresistance to the mesh layer. Well screen 10 of the present inventioneliminates the outer shroud thereby reducing costs of the well screenand reducing the outside diameter of well screen 10 relative to otherpremium mesh-type screens. Well screen 10 of the present invention isbelieved to address the long felt and yet unfulfilled need for a reducedoutside diameter well screen capable of operating in a wellbore.

Screen assembly 14 includes a drainage layer 16, filter layer 18, andsupport layer 20 further described with reference to FIG. 2. In anembodiment of the present invention screen assembly 14 is of a fullysintered construction, wherein the three-layers are diffusion bondedtogether. It is noted that multiple layers, for example more than onefilter layer 18, may be utilized.

Referring now to FIG. 2 wherein a partial cut away view of well screen10 is provided. Drainage layer 16 is positioned about and against basepipe 12. In the illustrated embodiment, drainage layer 16 is connectedto base pipe 12 by welds 22 thereby eliminating retainer ring typeconnectors. A rail 24, shown by hidden lines, may be connected acrossthe top to provide a safety edge to the assembly to avoid damage to wellscreen 10 during transport and installation. For example, weld 22 sealsfilter layer 18 to base pipe 12 to for ma seal to a similar level offiltration layer 18. The sealing may be accomplished by welding rail 24to base pipe 12 and to filter layer 18.

Drainage layer 16 is provided between base pipe 12 and mesh or filterlayer 18 to facilitate the flow of fluid into base pipe 12 when aperforation 13 in base pipe 12 or a portion of filter layer 18 isplugged. Drainage layer 16 of the present example is constructed ofwoven metal members shown as metal rods 26 and metal cable 28. Layer 16may be constructed of woven cable as both the warp and the weft or withrods as the warp and the weft. In the illustrated embodiment, layer 16is bonded together and to layers 18 and 20. In particular, layer 16 issintered to the inside diameter of mesh filter layer 18.

Filter layer 18 is constructed of sintered mesh type material. Forexample, filter layer 18 is made of multiple layers of woven wire clothsintered together. Filter layer 18 forms a porous medium sized toprovide accurate particle size control while maximizing the desiredfluid flow.

Support layer 20 is provided about mesh filter layer 18 and drainagelayer 16. In the illustrated embodiment, support layer 20 is sintered,diffusion bonded, to the outside diameter of filter layer 18. Supportlayer 20 is constructed of woven metal members shown as metal rods 26and metal cable 28. Layer 20 may be constructed of woven cable as boththe warp and the weft or with rods as the warp and the weft. In someexamples, screen assembly 14 may not include support layer 20.

It is understood that layers 16, 18, and 20 may be interconnected bymeans other than sintering. For example, filter layer 18 may besandwiched between drainage layer 16 and support layer 20. Layers 16 and18 may each be connected to base pipe 12 by welds 22 or may beinterconnected along rail 24 and connected to base pipe 12 by welds 22.

From the foregoing detailed description of specific embodiments of theinvention, it should be apparent that a well screen that is novel hasbeen disclosed. Although specific embodiments of the invention have beendisclosed herein in some detail, this has been done solely for thepurposes of describing various features and aspects of the invention,and is not intended to be limiting with respect to the scope of theinvention. It is contemplated that various substitutions, alterations,and/or modifications, including but not limited to those implementationvariations which may have been suggested herein, may be made to thedisclosed embodiments without departing from the spirit and scope of theinvention as defined by the appended claims which follow.

1. A well screen comprising: a base pipe having means for allowing fluidflow into the base pipe; and a screen assembly connected about a portionof the base pipe, wherein an outer shroud is not disposed over thescreen assembly.
 2. The well screen of claim 1, wherein the means forallowing fluid flow into the base pipe includes an inflow controldevice.
 3. The well screen of claim 1, wherein the screen assemblyincludes: a drainage layer positioned about the base pipe; and a filterlayer positioned over the drainage layer.
 4. The well screen of claim 3,wherein the drainage layer is connected to the base pipe by welding andthe filter layer and the drainage layer are interconnected.
 5. The wellscreen of claim 3, wherein the filter layer and the drainage layer areinterconnected by diffusion bonding.
 6. The well screen of claim 4,wherein the filter layer and the drainage layer are interconnected bydiffusion bonding.
 7. The well screen of claim 3, wherein the drainagelayer is constructed of woven metal rod and metal cable.
 8. The wellscreen of claim 7, wherein the metal rod and metal cable areinterconnected by diffusion bonding.
 9. The well screen of claim 8,wherein the drainage layer is connected to the base pipe by welding andthe filter layer and the drainage layer are interconnected.
 10. The wellscreen of claim 3, wherein the drainage layer is constructed of metalrods woven together as the warp and weft.
 11. The well screen of claim10, wherein the warp and weft are interconnected by diffusion bonding.12. The well screen of claim 11, wherein the drainage layer is connectedto the base pipe by a weld and the filter layer and the drainage layerare interconnected.
 13. The well screen of claim 3, wherein the drainagelayer is constructed of metal cable woven together as the warp and weft.14. The well screen of claim 13, wherein the warp and weft areinterconnected by diffusion bonding.
 15. The well screen of claim 14,wherein the drainage layer is connected to the base pipe by a weld andthe filter layer and the drainage layer are interconnected.
 16. A wellscreen apparatus used in a wellbore, the apparatus comprising: a basepipe having a means for allowing radial fluid entry; and a screenassembly having at least three layers interconnected by diffusionbonding, the screen assembly positioned about a portion of the base pipeand connected thereto.
 17. The apparatus of claim 16, wherein the screenassembly includes a drainage layer, a filter layer, and a support layer.18. The apparatus of claim 17, wherein the filter layer is constructedof sintered metal fabric.
 19. The apparatus of claim 16, wherein thescreen assembly includes: a drainage layer constructed of woven metalmembers; a filter layer constructed of sintered metal fabric; and asupport layer constructed of woven metal members, wherein the drainagelayer is positioned between the filter layer and the base pipe.
 20. Theapparatus of claim 16, wherein the screen assembly is connected to thebase pipe by welding and without being surrounded by a shroud member.21. A screen assembly connected about a base pipe, the screen assemblycomprising: a filter layer constructed of layers of woven metal clothsintered together; a drainage layer positioned between the base pipe andthe filter layer, the drainage layer sintered to the filter layer; and asupport layer constructed of woven metal rods and metal cable disposedabout the filter layer, the support layer sintered to the filter layer.